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Abstract:

In a print group for an inkjet printing apparatus a printing unit is
provided comprising a housing with print bars having print heads. A
transport unit is provided for a printing substrate. Drive and guidance
units are arranged per print bar which move the print bars independently
of one another in a perpendicular direction from a printing position into
a transport position and back. In a park unit racks are provided for
protective cap bars. A protective cap bar is provided per print bar which
when coupled to said print bar seals it. Print bars in an operating
position not provided for printing are in the transport position and are
coupled with associated protective cap bars. Print bars in said operating
position for printing are in the printing position and their associated
protective cap bars are arranged in the park unit racks.

Claims:

1. A print group for an inkjet printing apparatus, comprising: a printing
unit comprising a housing with print bars having internally arranged
print heads; a transport unit for a printing substrate; drive and
guidance units arranged per print bar in the housing of the printing
unit, said drive and guidance units moving the print bars independently
of one another in a perpendicular direction as viewed from the printing
substrate from a printing position situated adjacent to the printing
substrate into a transport position and back; adjacent to the transport
unit a park unit in a park position, and in the park unit racks are
provided for protective cap bars; and a protective cap bar being provided
per print bar which when coupled to said print bar seals it, print bars
in an operating position above the printing substrate not provided for
printing being in the transport position and being coupled with their
associated protective cap bars, and print bars in said operating position
and provided for printing being in the printing position and their
associated protective cap bars being arranged in the racks of the park
unit.

2. The print group according to claim 1 wherein: the transport unit has
side walls between which the printing substrate is directed; an
additional side wall being provided parallel to one of the side walls of
the transport unit, said additional side wall, together with the one side
wall of the transport unit, forming the park unit, and the racks for the
protective cap bars being provided on the transport unit one side wall
and the additional side wall.

3. The print group according to claim 2 in which the side walls of the
transport unit provide additional racks for the protective cap bars.

4. A method to position print bars having print heads and protective cap
bars provided to cover the print bars, said print bars being provided in
a printing unit, comprising the steps of: providing the print bars such
that they can be moved independently of one another in said printing unit
between a printing position in which a printing substrate can be printed
and a transport position above the printing position; providing the
protective cap bars such that they can be coupled to their print bars and
moved together with the print bars; and moving the print bars in an
operating position above the printing substrate not provided for printing
into the transport position and being covered by their associated
protective cap bars, and moving print bars in said operating position and
provided for printing into the printing position and their associated
protective cap bars being arranged in a park unit in a park position.

5. The method according to claim 4 in which for the case that all print
bars are used for printing and the printing unit with all print bars is
in the printing position the protective cap bars are arranged outside of
the printing substrate on associated racks in the park unit.

6. The method according to claim 4 in which for the case that individual
print bars are used for printing these print bars are moved into the
printing position and their protective cap bars are arranged outside of
the printing substrate on associated racks in the park unit; and the
remaining print bars, covered by their associated protective cap bars,
are moved into the transport position.

7. The method according to claim 6 in which the printing unit is moved
from the transport position into the park position, the print bars are
lowered in drive and guidance units, and the protective cap bars are
arranged in the park unit so that the print bars of the printing unit are
placed onto the protective cap bars upon lowering such that the print
bars are sealed by the associated protective cap bars.

8. The method according to claim 7 in which the printing unit is moved
from the park position into the operating position, and the print bars
that are not used for printing remain covered by the associated
protective cap bars while for the print bars that are used for printing
the associated protective cap bars remain in the park unit.

9. The method according to claim 8 in which the print bars used for
printing are moved from the transport position into the printing
position; and the print bars that are not used for printing remain
covered by their protective cap bars in the transport position.

10. The method according to claim 9 in which in a service position the
protective cap bars are stored on racks of a transport unit which
transports the printing substrate; and the printing unit is moved into
the park position so that the print heads are accessible.

11. A method to position print bars having print heads and protective cap
bars provided to cover the print bars, said print bars being provided in
a printing unit, and a transport unit being provided for a substrate to
be printed comprising the steps of: providing the print bars such that
they can be moved independently of one another in said printing unit
between a printing position above the printing substrate and in which the
printing substrate can be printed and a transport position above the
printing position; providing the protective cap bars such that they can
be coupled to their print bars and moved together with the print bars;
and moving the print bars in an operating position above the printing
substrate not provided for printing into the transport position and being
covered by their associated protective cap bars, and moving print bars in
said operating position and provided for printing into the printing
position and their associated protective cap bars being arranged in a
park unit in a park position laterally adjacent to said transport unit.

Description:

BACKGROUND

[0001] Inkjet printing apparatuses can be used for single or multicolor
printing of a printing substrate, for example a single sheet or a
belt-shaped recording material made of the most varied materials (paper,
for example). The design of such inkjet printing apparatuses is known;
see for example EP 0 788 882 E31. Inkjet printing apparatuses that
operate according to the Drop-on-Demand (DoD) principle, for example,
have as a printing unit a print head or multiple print heads with nozzles
comprising ink channels, the activators of which nozzles--controlled by a
printer controller--induce ink droplets in the direction of the printing
substrate, which ink droplets are directed onto the printing substrate in
order apply print dots there for a print image. The activators can
generate ink droplets thermally (bubble jet) or piezoelectrically.

[0002] Given low print utilization of the inkjet printing apparatus, not
all nozzles of the inkjet print heads are activated in the printing
process; and many nozzles have idle time periods (print pauses), with the
result that the ink in the ink channel of these nozzles is not moved. Due
to the effect of the evaporation from the nozzle opening, the danger
exists here that the viscosity of the ink then changes. This has the
result that the ink in the ink channel can no longer move optimally, and
for example cannot exit from the nozzle. In extreme cases, the ink in the
ink channel dries completely and blocks the ink channel, such that a
printing with this nozzle is no longer possible.

[0003] The drying of the ink in the nozzle can be prevented in that
printing occurs from all nozzles within a predetermined cycle. This cycle
can be adjusted corresponding to the print utilization. Individual points
can thereby be applied in unprinted regions of the printing substrate, or
print dot lines can be printed between print pages. In addition to
unnecessary ink consumption and additional wear of the print heads, this
method can lead to disruptions in the print image.

[0004] These problems in particular occur in color printers. Here, for
example, print bars with print heads are arranged in a fixed position
relative to one another as a printing unit. For example, print bars with
five respective print heads can be provided, respectively one print bar
for the colors black, cyan, magenta, yellow. Here the problem exists that
one or more colors cannot be used, for example in black-and-white
printing. Multiple cleaning cycles are then required in order to make the
unused print heads run well again.

[0005] From U.S. Pat. No. 6,578,945 B2 it is known to avoid the drying out
of the nozzles in an inkjet printing apparatus with multiple print heads
in that the nozzles are closed with protective caps. The ink dispensed in
the cleaning of the nozzles is thereby captured by the protective caps.
In order to apply the protective caps onto the nozzles, the printing unit
with the print heads is moved upward, away from the printing substrate;
the protective caps are driven into the intervening space between
printing unit and printing substrate; and thus the print heads are
thereby cleaned. The protective caps are moved upward onto the print
heads via an elastic force, wherein the print heads are covered. The
protective cap unit remains in this position until the printing unit
should be used again for printing.

[0006] In US 2007/0157962 A1, an inkjet printing apparatus is described in
which the print head can be moved upward and perpendicular away from the
printing substrate between a printing position and a position in which no
printing is implemented. In this printing position a protective cap
comprising rubber can be applied onto the nozzles of the print head.

[0007] From DE 10 2005 034 029 A1 an inkjet printing apparatus is known
with multiple print heads arranged serially in the transport path of the
printing substrate. The inkjet print heads successively print a resulting
print image on the printing substrate. Individual inkjet print heads can
be deactivated and shifted laterally (for example in order to service
these) while the remaining print heads can continue printing.

[0008] DE 197 26 642 C1 describes a device to position an inkjet print
head and a cleaning and sealing device. The inkjet print head can be
pivoted from a printing position into a cleaning position and back again.
A cleaning and sealing device can be moved onto the inkjet print head and
away from this again. The cleaning and sealing device has a sealing cap
and a wiping lip.

SUMMARY

[0009] It is an object to specify a print group for an inkjet printing
apparatus, in which print group print bars comprising print heads and
protective cap bars provided to seal the print bars can be positioned
such that print bars that have a printing pause can be sealed with a
protective cap bar while printing can take place with the remaining print
bars.

[0010] In a print group for an inkjet printing apparatus a printing unit
is provided comprising a housing with print bars having print heads. A
transport unit is provided for a printing substrate. Drive and guidance
units are arranged per print bar which move the print bars independently
of one another in a perpendicular direction from a printing position into
a transport position and back. Adjacent to the transport unit a park unit
is provided, and in the park unit racks are provided for protective cap
bars. A protective cap bar is provided per print bar which when coupled
to said print bar seals it. Print bars in an operating position not
provided for printing are in the transport position and are coupled with
their associated protective cap bars. Print bars in said operating
position and provided for printing are in the printing position and their
associated protective cap bars are arranged in the racks of the park
unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a principle, perspective presentation of a portion of a
print group with a printing unit;

[0012] FIG. 2 is a principle presentation of a printing unit in which the
print bars are entirely individualized;

[0013] FIG. 3 is a principle presentation of a printing unit in which the
print bars are partially individualized;

[0014] FIG. 4 is a principle presentation of a front view of the printing
unit according to

[0015] FIG. 1;

[0016] FIG. 5 is a principle, perspective presentation of the printing
unit, in which the printing unit is in the operating position and
individual print bars are in the printing position;

[0017] FIG. 6 is a principle, perspective presentation of the printing
unit in the operating position when all print bars are in the transport
position;

[0018] FIG. 7 is a principle, perspective presentation of the printing
unit when the printing unit is moved into the park position;

[0019] FIG. 8 is a principle, perspective presentation of the printing
unit when the printing unit is in the park position;

[0020] FIG. 9 is a principle, perspective presentation of the printing
unit in the operating position when the printing unit is in the park
position and the print bars are sealed by their protective cap bars;

[0021] FIG. 10 is a principle, perspective presentation of the printing
unit in the park position when the print bars are moved into the
transport position;

[0022] FIG. 11 is a principle, perspective presentation of the printing
unit when the printing unit is moved from the park position to the
operating position;

[0023] FIG. 12 is a principle, perspective presentation of the printing
unit when the printing unit is in the operating position;

[0024] FIG. 13 is a principle, perspective presentation of the printing
unit when the printing unit is in the operating position, one print bar
is in the printing position and the remaining print bars are in the
transport position, covered by their protective cap bars; and

[0025] FIG. 14 is a principle, perspective presentation of the printing
unit when the printing unit is in the service position.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] For the proposes of promoting an understanding of the principles of
the invention, reference will now be made to the preferred
embodiment/best mode illustrated in the drawings and specific language
will be used to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby intended, and
such alterations and further modifications in the illustrated embodiment
and such further applications of the principles of the invention as
illustrated as would normally occur to one skilled in the art to which
the invention relates are included.

[0027] In the print group according to the preferred embodiment, the print
bars comprising print heads form a printing unit. In the printing unit
the print bars can be moved independently of one another between a
printing position (in which a printing substrate can be printed) and a
transport position above the printing position. One protective cap bar is
provided per print bar, which protective cap bar can be designed as a
trough and can then seal all print heads of a print bar. It is also
possible to execute the protective cap bar such that the protective cap
bar respectively has one protective cap per print head. The print bars
that are not used for printing are situated in the transport position and
can be covered by their associated protective cap bars while the print
bars used for printing are in the printing position, wherein the
associated protective cap bars can be arranged outside of the printing
unit.

[0028] Given the print group according to the preferred embodiment it is
ensured that the following requirements for the position of the print bar
with the print heads are satisfied: [0029] The print bars in the
printing unit can adopt a printing position in which the print bars are
positioned with the print heads over the printing substrate. [0030] The
print bars in the printing unit can adopt a transport position in which
the printing unit can be moved without damaging the print heads. [0031]
The print bars can be placed on protective cap bars in a park position of
the printing unit in order to avoid a drying out of the nozzles of the
print heads during print pauses. [0032] The printing unit can adopt a
maintenance position in which, for example, the print heads are
accessible in order to be able to clean their nozzle surfaces.

[0033] The print group according to the preferred embodiment therefore has
the following advantages: [0034] The print heads on the print bars
cannot dry out given non-use since these print bars are respectively
sealed tight with a protective cap bar. [0035] The previously unused
print bars are immediately ready for use if necessary. [0036] Long
reactivation periods and reactivation jobs are not necessary. [0037] The
maintenance cost is significantly reduced since the unused print bars are
protected against external influences, for example contamination or
mechanical damage. Also, no additional ink is consumed and the wear of
the print heads is reduced. The print quality is increased by reducing
the background on the printing substrate. [0038] Each print bar is
individually accessible or protected in each position via the use of the
transportable protective cap bars, and can also be parked long-term.
Additional, cost-intensive, individual positions that the print heads
must take up are done away with. [0039] Nevertheless, the advantages of a
complete unit relative to completely individualized print bars remain due
to the integration of the print bars into a printing unit.

[0040] The design of a print group with a printing unit 2 and a transport
unit 8 for a printing substrate 7 results in principle from FIG. 1 for
the purpose of explanation. The printing unit 2 comprises, for example,
six print bars 1a through 1f that respectively provide print heads 12
(FIG. 2, 3). The printing unit 2 has a housing 9 with side walls 9.1 and
9.2 between which the print bars 1 are arranged. The side walls 9.1 and
9.2 of the housing 9 provide drive and guidance units 5 for the print
bars 1 with which the print bars 1 can be moved independently of one
another within the housing, perpendicular to the plane of the printing
substrate 7. Furthermore, in the print group a drive and guidance unit 6
is provided that can be attached to the printing unit 2 and over which
the printing unit 2 can be moved parallel to the plane of the printing
substrate 7 within the print group. The printing unit 2 can be moved via
the drive and guidance unit 6 from an operating position (in which the
printing unit 2 is arranged above the printing substrate 7 to be printed)
into a park position (that is situated next to the transport unit 8 for
the printing substrate 7).

[0041] The transport unit 8 has side walls 8.1 and 8.2 between which
transport rollers 10 for the printing substrate 7 are borne. Furthermore,
racks 4.1 for protective cap bars 3 (called front cap rack 4.1) are
arranged at the side walls 8.1 and 8.2 of the transport unit 8. The
protective cap bars 3 are provided to seal print bars 1 that are not used
in the printing. One protective cap bar 3 is respectively provided per
print bar 1, wherein the protective cap bar 3 is designed as a trough for
all print heads of an associated print bar 1. The protective cap bars 3
can respectively have an outflow for the ink collected in the trough (not
shown in Figures). Furthermore, an additional side wall 11 is provided
adjacent and parallel to the side walls 8.1 and 8.2 of the transport unit
8, which side wall 11--with the side wall 8.2 of the transport unit
8--forms a park unit 13 for the printing unit 2, wherein additional racks
4.2 for the protective cap bars 3 (called rear cap rack 4.2) are provided
between the side wall 11 and the side wall 8.2 so that the protective cap
bars 3 can be borne on the rear cap rack 4.2 in the park unit 13 in the
park position. Four protective cap bars 3a through 3d are drawn as an
example in the rear cab rack 4.2 in FIG. 1.

[0042] During operation, the printing unit 2 can assume two positions,
wherein with the drive and guidance unit 6 the printing unit 2 can be
moved from the one position into the other position and back: [0043]
The printing unit 2 can be in the operating position in which the
printing unit 2 is situated over the printing substrate 7. This case is
shown in FIG. 1. [0044] The printing unit can be in the park position in
which, in addition to the transport unit 8 for the printing substrate 7,
the printing unit 2 is arranged in the park unit 13.

[0045] The print bars 1 in the printing unit 2 can likewise adopt two
positions: [0046] The print bars 1 can be in the printing position in
which the print heads can print to the printing substrate 7. For example,
in FIG. 1 the print bars 1a through 1d are in the printing position.
[0047] Via their drive and guidance unit 5 the print bars 1 can be
brought upward into a transport position in which no printing is
possible. In the transport position the printing unit 2, with the drive
and guidance unit 6, can be moved parallel to the printing substrate 7
without the print heads of the print bar 1 being able to be damaged. For
example, in FIG. 1 the print bars 1e, 1f are in the transport position.
[0048] In the park position in the park unit 13 the print bars 1 can be
moved in their drive and guidance units 5 from the transport position
into the park position, in which the print bars can be coupled with the
protective cap bars 3. Counter to this they can likewise be brought from
the park position into the transport position again, and in fact with or
without protective cap bars 3.

[0049] The protective cap bars 3 can thereby be coupled with the
associated print bars 1 in order to seal these, or they can be released
by these. For this the protective cap bars 3 can selectively [0050] be
borne in the front cap rack 4.1; [0051] be borne in the rear cap rack
4.2; [0052] be coupled with the associated print bars 1 in order to seal
these.

[0053] In FIG. 1 the protective cap bars 3a through 3d are borne on the
rear cap rack 4.2 while the protective cap bars 3e and 3f are coupled
with the print bars 1e and 1f (not visible in FIG. 1).

[0054] FIG. 2 shows as an example a printing unit 2 with four print bars
1a through 1d with five respective print heads 12, wherein each print bar
1 can be operated independently of the others. Each print bar 1 can thus
be moved independently of the other print bars 1 from the print position
into the transport position and back, and thus can be brought from a
printing position (in which the printing substrate 7 can be printed) into
the transport position at a distance above the transport unit 8 for the
printing substrate 7, in which transport position the printing unit 2 can
be moved as a whole without damaging the print heads 12.

[0055] FIG. 3 shows as an example the printing unit 2 that, corresponding
to FIG. 2, has print bars 1 with print heads 12. In contrast to FIG. 2,
multiple print bars 1a through 1c have been assembled in the manner of a
block in FIG. 3 and therefore can be moved together. In contrast to this,
the print bar 1d can be operated individually.

[0056] The printing unit according to FIG. 1 is designed so that the print
bars 1 can be operated both corresponding to FIG. 2 and corresponding to
FIG. 3.

[0057] A printing unit according to FIGS. 1 through 3 can be used in color
printing, for example. A print bar 1 can then respectively be provided
whose print heads 12 generate print dots of one color, for example the
colors black, cyan, magenta, yellow. The print heads 12 of the print bar
1 can thereby be arranged across the width of a printing substrate 7 in
order to be able to print across its width.

[0058] A principle image of the part of the print group according to FIG.
1 with the printing unit 2 and the transport unit 8 for the printing
substrate 7 in a front view can be learned from FIG. 4. A print bar 1a is
in the printing position; the other print bars 1b through 1d are drawn in
the transport position. The print bars 1b through 1d in the transport
position are respectively protected by a protective cap bar 3b through
3d, wherein each protective cap bar 3 seals one print bar 1.

[0059] FIG. 5 shows the section of the print group in comparison to FIG. 1
from the opposite side. The printing unit 2 is in the operating position.
Of the printing unit 2, the housing 9 with the side walls 9.1 and 9.2,
the print bars 1a through 1f and the drive and guidance units 5 (one
respectively per print bar 1a through 1f) are shown. Of the print bars 1a
through 1f, the print bars 1e, 1f are covered with a protective cap bar
3e, 3f; these print bars 1e, 1f are situated in the transport position,
above the printing position. The remaining print bars 1a through 1d are
in the printing position, and in addition to the print bars 1a through 1d
their protective cap bars 3a through 3d are parked on their racks 4.2
between the side wall 8.2 and the side wall 11 (rear cap rail 4.2).
Printing can thus take place with the print bars 1a through 1d while the
print bars 1e, 1f (that have a printing pause) are covered with a
protective cap bar 3e, 3f so that the nozzles of the respective print
heads do not dry out.

[0060] FIG. 6 shows the printing unit 2 in the operating position when the
print bars 1a through 1d of the printing unit 2 have been moved upward
(in the direction of the arrows PF1) from the printing position into the
transport position. The attitude of the housing 9 for the print bars 1
thereby remains unchanged. Only the print bars 1a through 1d are moved
upward from their drive and guidance units 5. The print bars 1e, 1f
remain in the position of FIG. 5, and likewise the protective cap bars
3e, 3f. Four protective cap bars 3a through 3d are borne next to the
transport unit 8 on the cap rack 4.2 in the park unit; and two protective
cap bars 3e, 3f cover their print bars 1e, 1f.

[0061] FIG. 7 shows the print group when the printing unit 2 is driven
from the operating position into the park position (Arrow PF2). The
printing unit 2 is thereby moved in the direction of the arrow PF2 with
the aid of the drive and guidance unit 6. In this operating position the
print bars 1a through 1f are in the transport position. The transport
unit 8 and the printing substrate 7 are thereby released. Only the print
bars 1e, 1f are covered by their protective cap bars 3e, 3f.

[0062] FIG. 8 shows the case in which the printing unit 2 has reached the
park position. The printing unit 2 now lies between the side wall 8.2 of
the transport unit 8 and the side wall 11 of the park unit 13. The print
bars 1e, 1f are thereby covered by their protective cap bars 3e, 3f; and
the protective cap bars 3a through 3d for the print bars 1a through 1d
are located in the park position on the rear rack 4.2.

[0063] In the park position of the printing unit 2 the print bars 1 can be
moved downward in their guidance and drive units 5 in the direction of
the arrow PF3 (FIG. 9), wherein the print bars 1 can be sealed with their
protective cap bars 3. The protective cap bars 3 and print bars 1 can be
connected with one another by a seal (not shown). In FIG. 9 the
protective cap bars 3a through 3d are still situated in the rear cap rack
4.2; and the protective cap bars 3e, 3f are coupled to the print bars 1e,
1f. If the printing unit 2 has reached the park position, all print bars
1 are covered by their respective protective cap bars 3.

[0064] If the printing unit 2 should be used again for printing, wherein
the printing should only be conducted with the print bar 1d, for example,
the print bars 1a through 1c, 1e through 1f that are not provided for the
printing (together with coupled protective cap bars 3a through 3c, 3e
through 3f; not visible in FIG. 10) are driven upward from the park
position (arrow PF4) while the print bar 1d provided for the printing
detaches from its protective cap bar 3d and is driven upward without
this; and the protective cap bar 3d remains in the park position on its
rack 4.2. FIG. 10 shows this case.

[0065] The printing unit 2 is finally moved with the aid of the drive and
guidance unit 6 from the park position into the operating position, in
the direction of the arrow PF5 (FIG. 11). The print bars 1 are moved into
the transport position, wherein the print bars 1a through 1c, 1e, 1f are
covered with their protective cap bars 3a through 3c, 3e through 3f. Only
the print bar 1d is not protected by its protective cap bar 3d.

[0066] The operating position of the printing unit 2 is achieved in FIG.
12. The print bar 1d provided for printing can now be brought downward in
its drive and guidance unit 5 into the printing position, wherein the
print bars 1a through 1c, 1e, 1f that are not used for the printing
remain in the transport position with coupled protective cap bars 3a
through 3c, 3e, 3f. FIG. 13 shows this operating position. The protective
cap 1d provided for the printing is in the printing position; the
protective cap bar 3d for this print bar 1d lies in the rear cap rack
4.2. The remaining print bars 1a through 1c, 1e, 1f remain in the
printing unit 2 in the transport position, wherein these print bars 1a
through 1c, 1e, 1f are sealed by their protective cap bars 3a through 3c,
3e, 3f.

[0067] Finally, the printing unit 2 can be brought into a service position
(FIG. 14). In the service position the print bars 1 are freely accessible
and can be cleaned, for example. For this the printing unit 2 is located
in the park position, the print bars 1 are lowered into the park
position; and they can additionally be moved further downward out of the
housing 9 by their drive and guidance units 5. However, the protective
cap bars 3 remain above the printing substrate 7 on the front cap rack
4.1.

[0068] In FIG. 14 two pins 14 are drawn per protective cap bar 3, for
example, which pins 14 can engage into associated bores of the print bars
in order to connect these with one another.

[0069] A large advantage of the method according to the preferred
embodiment exists in that the printing unit 2 is executed such that each
print bar 1 can be operated individually: [0070] The printing unit 2
can be in the park position, wherein the print bars 1 can be sealed by
their protective cap bars 3 or be decoupled from their protective cap
bars 3. [0071] In the printing unit 2 the print bars 1, with or without
protective cap bars 3, can be moved from the transport position into the
park position and back. [0072] In the printing unit 2 the print bars 1
can be in the print position, i.e. situated over the printing substrate 7
without protective cap bar 3. [0073] In the printing unit 2 the print
bars 1 can be in the transport position, in which they have been moved
upward from the print position in their drive and guidance unit 5. [0074]
In the printing unit 2 the print bars 1 can be in the transport position,
in which they have been moved upward from the print position in their
drive and guidance unit 5 and are covered by their protective cap bars 3.

[0075] All print bars 1 can likewise be operated correspondingly, together
with or separately from one another. The protective cap bars 3 can
additionally be borne on the front cap bar 4.1 on the transport unit 8,
and the printing unit can be brought into a service position in which the
print heads are freely accessible.

[0076] In the explanation of the print group according to the preferred
embodiment, its construction design--in particular of the printing unit
2--has not been discussed in detail. For example, the drive and guidance
units 5, 6 can be of known design; for example, they can have a step
motor that moves the print bars 1 or the printing unit 2 on the guidance
units 5 or 6. In the Drawing Figures the transport unit 8 is configured
so that the printing substrate 7 is directed past the printing unit 2 in
a straight line (FIG. 4). However, it is also possible to feed the
printing substrate 7 past the printing unit 2 in an arc. The print bars 1
can then be arranged in a star shape in the printing unit 2. Since the
print bars 1 can be moved independently of one another by their drive and
guidance units 5, in this case the desired clearance between the
respective print bars 1 and the printing substrate 7 can also be set. The
printing substrate 7 is presented in the form of webs in the Drawing
Figures. The printing substrate can also comprise individual sheets.

[0077] Although a preferred exemplary embodiment is shown and described in
detail in the drawings and in the preceding specification, it should be
viewed as purely exemplary and not as limiting the invention. It is noted
that only a preferred exemplary embodiment is shown and described, and
all variations and modifications that presently or in the future lie
within the protective scope of the invention should be protected.

Patent applications by Andreas Mueller, Baldham DE

Patent applications by Sebastian Wachter, Muenchen DE

Patent applications in class With means to scan fluid ejector relative to the receiving medium

Patent applications in all subclasses With means to scan fluid ejector relative to the receiving medium